When I take a long exposure shot of say 30 seconds, it takes about another 30 seconds before I can see the result. Is this normal or is my memory card too slow? When I take an 8 second shot the result is there within 1 second but a 10 second shot takes about another 10 seconds before you can see the result and a 1 minute shot seems to take about another 30 seconds to 1 minute to produce the goods. (haven't actually timed it)

My card is a Sandisk Ultra II 4GB SDHC 15MB/s which I know isn't the fastest card but neither is it the slowest, just wondered if it is the camera taking the time to process the photo or the simply the card being slow?

I also have as a spare, a Kingston Elite Pro 2GB with a speed of 50x which I have no idea what 50x speed actually means in terms of MB/s but it appears to be not noticably different to the Sandisk in terms of speed

If you are doing a lot of long exposure with exactly the same settings, you may find it worthwhile to manually take a dark frame and subtract it from the shots. Basically take a shot with the lens cap in place, so this will only capture the long duration noise. Then use whatever software you have to subtract it from the images. Of course, you're trading photographing time saving with additional manual processing time.

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If I had to guess I'd put my bets on the dark-frame subtraction-thingy - as long as normal daylight shooting behaves inconspicuous.